The present invention relates to machines for attaching plates to railroad ties or preplaters.
It is well-known that the two rails of railway track must be accurately aligned with each other to maintain parallelism and accurately spaced to define gauge. One method of achieving the gauge and parallelism uses one prelaid rail as a reference and applies a second rail relative thereto. This was either done by hand or required a carriage rolling on the fixed rail. A typical example of the prior art is U.S. Pat. No. 2,730,962 wherein tie plates are accurately aligned relative to a first laid rail to provide the required gauge and to assure parallelism.
Another method of assuring the gauge and parallelism of the tracks is the method of preplating, wherein the tie plates are secured to the ties before the ties are installed or placed on the ground. The preplaters date from the early manually inserted ties of U.S. Pat. No. 703,755, to a very sophisticated conveying, plating, and laying system of U.S. Pat. No. 3,701,320. A complete system of U.S. Pat. No. 3,701,320 conveys ties having predrilled holes in a first path to receive plates having spikes pending therefrom in a second path so as to intersect placing the spikes and plates in the predrilled holes. The assembled tie and plate are then secured by a hammering station and transmitted further down the line. Other preplating systems presently available include feeding and transporting the tie lengthwise through a hammering station, securing a first plate, and then manually measuring the gauge before securing the second plate.
An older philosophy of determining gauge is illustrated in French Pat. No. 91,796 wherein the tie is conveyed to a station wherein a pair of notches are formed to receive the tie plates and holes are drilled for the spikes.
Assessment of the prior art reveals a need for a mechanically simple preplating apparatus which can accurately align, space, and secure a pair of plates to a tie to assure the gauge and parallelism of the tracks to be placed therein and is capable of operating at a high speed.